Two Pointers

The Two Pointers pattern is a coding technique used to solve problems involving arrays or sequences by using two pointers that move through the array simultaneously. This pattern is particularly useful for optimizing solutions where you need to find a specific subarray or a pair of elements that satisfy certain conditions.

Here’s a step-by-step explanation of the Two Pointers pattern:

1. Initialize Pointers: Start with two pointers, typically initialized to the beginning of the array or sequence.
2. Move Pointers: Move the pointers through the array while considering specific conditions. The pointers can move towards each other, away from each other, or in any specified direction.
3. Condition Check: At each step, check the condition or criteria you’re interested in. This might involve comparing elements pointed to by the two pointers or evaluating a specific property.
4. Adjust Pointers: Depending on the condition check, adjust the pointers accordingly. You might move one or both pointers based on whether the current configuration satisfies the condition or not.
5. Repeat: Continue moving and adjusting the pointers until they meet, cross each other, or cover the entire array.

The Two Pointers pattern is especially helpful for optimizing time complexity, often leading to linear or near-linear solutions. It’s commonly used to solve problems like finding subarrays with a specific sum, detecting pairs with certain properties, or performing other comparisons within an array.

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